Check out this short article

http://en.wikipedia.org/wiki/Winchester_Model_1892

They claim original calibers were .32-20, .38-40, .44-40, .25-20, .218 Bee. I am not a Winchester collector....

It also states the factory would custom chamber a gun. The 357 mag was introduced in 1934, about 11 years before the 92 was phased out. So it is possible. If it is a 100% factory, then it is a rare bird. You need to get the serial number, then contact the Cody Firearms Museum.

Pete

http://www.damascus-barrels.com/Movie.html